Carborane Burning Rate Catalysts

摘要

New carborane burning rate accelerators designed for use in solid propellants, without the problems associated with current accelerators, have been prepared. High molecular weight, non-volatile derivatives of bis(1-carboranylmethyl) and bis-(1-carboranylethyl) ethers were synthesized and evaluated for compatibility in HTPB binders as well as compatibility and ballistic effects in aluminized HTPB propellants. The branched unsaturated carborane derivative, 3,7-dimethyl-2,6-octadienyl-bis-(1-carboranylmethyl)ether, has proved to be compatible with cured HTPB at the 60% level. Propellants containing high levels of this carborane showed no evidence of plasticizer bleeding over long periods of storage. Also propellants containing this derivative have exhibited higher burning rates than those containing equivalent amounts of NHC. Several alkyl oxygen ether derivatives of bis-(1-carboranylmethyl)ether have been prepared and partially evaluated. Both the butoxyethoxymethyl and isobutoxyethoxymethyl derivatives are more effective as burning rate accelerators than NHC. These materials, although compatible with cured HTPB at the 60% level, exude slightly from test propellants. Two pentaborane carboranes were prepared and evaluated as propellant plasticizers. It was found that the small closo-carborane cage is highly susceptible to oxidative degradation and consequently of limited value as a burning rate accelerator. (Author)